CVE-2026-117691— Keycloak-services: keycloak-services: saml redirect binding signature bypass via percent-encoded parameter names

Quick assessment

Affected

Red Hat Red Hat Build of Keycloak

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Keycloak 的 SAML HTTP-Redirect 绑定实现中发现了一个漏洞。该问题源于服务器会处理经过百分号编码的参数名（例如 %53AMLResponse），而签名验证逻辑仅检查字面参数名。攻击者可利用这一差异，提交精心构造的未签名 SAML 消息，使服务器将其误当作合法签名的消息进行处理，从而导致联邦用户的账户被完全接管。

CVSS 9.1 · Critical Updated Nov 05, 2026

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

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Vulnerability Information

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Vulnerability Title

Keycloak-services: keycloak-services: saml redirect binding signature bypass via percent-encoded parameter names

Source: CVE Program / CVE List V5

Vulnerability Description

A flaw was found in the SAML HTTP-Redirect binding implementation of Keycloak. The issue occurs because the server processes percent-encoded parameter names (like %53AMLResponse) while the signature verification logic only checks literal parameter names. An attacker can use this discrepancy to provide a crafted, unsigned SAML message that the server processes instead of a legitimately signed one, leading to full account takeover of federated users.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Source: CVE Program / CVE List V5

Vulnerability Type

密码学签名的验证不恰当

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE
Red Hat	Red Hat Build of Keycloak	-	`cpe:/a:redhat:build_keycloak:`
Red Hat	Red Hat Build of Keycloak	-	`cpe:/a:redhat:build_keycloak:`
Red Hat	Red Hat Single Sign-On 7	-	`cpe:/a:redhat:red_hat_single_sign_on:7`

II. Public POCs for CVE-2026-117691

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-117691

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Other References for CVE-2026-117691 (2)

https://access.redhat.com/security/cve/CVE-2026-117691 vdb-entry x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2561977 issue-tracking x_refsource_REDHAT

https://www.cve.org/CVERecord?id=CVE-2026-117691

Same Patch Batch · Red Hat · 2026-11-05 · 3 CVEs total

CVE-2026-107912	7.7 HIGH	Io.quarkus/quarkus-vertx-http: quarkus-vertx-http: authorization bypass in management inte
CVE-2026-123036	5.5 MEDIUM	CVE-2026-123036

IV. Related Vulnerabilities

Same product: Red Hat Build of Keycloak

Same vendor: Red Hat

Same weakness: CWE-347